A serious problem in connection with drug preparation, drug administration or other similar handling, is the risk that medical and pharmacological staff are exposed to drugs or solvents which might escape into the ambient air. This problem is particularly serious when cytotoxins, antiviral drugs, antibiotics and radiopharmaceuticals are concerned. Other hazardous areas may be sampling taking such as samples relating to virus infections or the like. For these reasons, there has been a need of safer systems for handling and administrating drugs and other medical substances.
Accordingly, U.S. Pat. No. 4,564,054 (Gustaysson) discloses a fluid transfer device for transferring a substance from one vessel to another vessel while avoiding leakage of liquid and gas contaminants. The disclosed device comprises a first member designed as a hollow sleeve and having a piercing member provided with a passageway. The piercing member is attached to the first member which has a first barrier member at one end just opposite the tip of the piercing member. Thereby, the piercing member can be passed and retracted through the first barrier member which seals one end of the first member. The fluid transfer device further comprises a second member which is attached to or attachable to one of the vessels or to means arranged to communicate therewith. The second member has a second barrier member, and mating connection means arranged on the first and second members for providing a releasable locking of the members with respect to each other. In the connected position of the first and second members, the barrier members are located in such a way with respect to each other that the piercing member can be passed therethrough.
The barrier members are liquid and gas-proof sealing members sealing tightly after penetration and retraction of the piercing member to prevent leakage of liquid as well as gas contaminants. Another example using a barrier member is the U.S. Pat. No. 3,900,028 in which an injection site for a liquid bottle having a first cylindrical member interposed of a second cylindrical member and a barrier member arranged therebetween is disclosed. During manufacturing of the injection site, the second member is telescopically inserted into an opening at a lower end of the first member. The barrier member is tightly compressed in the longitudinal direction of the first and second members. The first cylindrical member is thereafter fixed to the second cylindrical member by means of a rib on the first cylindrical member and a groove on the second cylindrical member. The rib of the first cylindrical member is formed by deforming the lower edge of the first cylindrical member by subjecting it to heat and pressure during the manufacturing of the injection site.
Barrier members used in the above mentioned applications are usually made from a natural or synthetic rubber or a rubber like material. However, it has been found that medical devices such as those mentioned above suffer from a limited working life. For example, by compressing the barrier member during manufacturing too much, the barrier membrane can be damaged, likewise, by compressing the barrier membrane too little, the medical device can leak. It has further been realized that the compression itself can cause a reduced working life for the medical devices.